Fluid displacement mechanism



May 28, 1940.

FLUID DISPLACEMENT MECHANISM Filed Sept. 19, 1938 4 Sheets-Sheet 1 J. w.FORRE'STER ET AL,

Wu Y2 SZmjd May 28, 1940. J. w. FORREVSTER ET AL FLUID DISPLACEMENTHECHAN ISIQ Filed Sept. 19. 1938 I l [J/ 4 Sheets-Sheet 2 May 28, 1940.

J. w. FORRESTER Err AL ,520

DISPLACEME Filed Sept. ts-S 7 I I Ill Z 27 I 7 I II In |H| 1 Hil I II IMlln H i: l l

44 fly. 8

Patented 'May 28, 1940 um'rsos rATEs PATENT o-FF cs FLUID DISPLACEMENTMECHANISM Jesse .W. Forrester, Marshfield, and J aines V.

Sheridan, Powers, Oreg.

Application September 19, 1938, Serial '1 Claims.- (01. 230 -18?) Ourinvention relates to fluid displacement mechanisms, and-particularly toair compressors,

having a plurality (two-or more) of fixed piston operatedfluid-displacement or compressor units radially disposed about a drivingcam, and bell crank piston-return mechanisms adapted to lower one pistonas the'next piston: is raised by the cam.

An object of our invention is to provide a compressor having largecapacity, small size for said capacity, and'ruggedsimplicity. Otherobjectives will be apparent as we proceed. Fig. 1, of the accompanyingdrawings is a plan view showing Fig. 2 .is aside View; Fig. 3 is asection on 3-3 of Fig. 1; Fig. 4 is a section on 4--4 of Fig. 2; Fig. 5is a side view'of the piston-return mecha-. nism shown in Fig. 4; Fig. 6is a partial section cut as shown in .Fig. 4, but showing another formof piston-return mechanism; Fig. '7 shows another piston-returnmechanism; Fig. .8 is a plan view of thepiston-return mechanism shown inFig. '7, with one of the arms. provided with ad- -justment; Fig. 9 is aside view of Fig. 8 Fig.'l0 is a plan view of the piston valve; Fig. 11is a plan view of the valves in the cylinder head; Fig. l2-|2.of Fig.11; Fig. 13 is a 12 is a. section on section on l3-I3 of Fig. 11.

, Thruout the drawings and :the specification similar numerals refer .tosimilar parts.

'The increased use of air, especially in the field, has opened upamarket for a simple and rugged machine that has a and that is cheap tobuild, .keep up, and service. The compressor shown in Figs. 1, 2, 3, and4,

may be equipped with'the other piston-return mechanisms shownan'ddescribed, also,. it may be equipped with other types of valves, nonebeing shown.

The major portion of is frusto-conically shaped interiorly andexter'iorly, with its. upperend merged into a cylindrical neck-:2 andits lower 'end into a cylindrical base 3 pierced bythe holes 4 thruwhich the means used to secure the compressor toits support maybepassed. 'The neck 2 is bored for the reception of the snugly fittingboss 5 formed below the outstanding shoulder-formingv flange Son thecylindricalbarrel portion 1 which depends-from the lowercover 8 of thecam chamber casing 9. The flange 6 gives support to the lower cover '8directly. and indirectlyto the cam chamber casing 9, and thruit arepassed the cap screws ID by means of which said cover is secured to theneck ".2 of the base I. The cylinan eight unit compressor; I

"is passed the stud bolts thereiniand free to large capacity for itssize,.

the compressor base I dricalcam chamber casing .9 is bored top andbottom concentrically for the reception-of the snugly fitting bosses Hand I2 formedbeyond the outstanding shoulder-forming fflanges i3 and Mon the lower cover, 8 and the upper-cover I5 respectively. The capscrews, l6 and 11, .respectively, pass thru the flanges 13 and i4. andinto thecylindrical cam chamber casing 9 and therebysecurethe covers 8and IE to said casing. The peripheral face, l8 of'the. casing 9 is boredradially for the reception of the snugly 7 fitting boss 19 formed on.each cylinder 2t. The boss 19 is in reality an extension of the cylindrical wall 2| of the cylinder 20 beyond the outstandingshouldereforming flange 22 'thru which 23 by means-of which thecylinders are secured to the casing 9. Within each cylinder is a piston24 provided with a plurality of sealing rings 25 and reciprocable withinsaid cylinder thruthe agency of 20 the connecting rod 26 hingedlysecured to said piston by thewrist pin 21' which is press, fitted turnin the bearings. 28 pro: vided in the bosses29 on the piston wall"30 Theconnecting rod 26 is'bifurcated tostraddle 5 Y the hub of each leg'26Aof the connecting rod, 39 V and whose outer race 36 is free to rotate.The hub 35 alsohas an outwardly extending boss 31 to provide, adequatebearing area on ,the wrist pin'33 for, the loadsthat may come upon theconnecting rod and toprovide a pintle bearing. for 35 one .end of theradius link 38. The hub 38A on the opposite end of each radius link ispush fitted upon'the hinge pin 39 supported by the bearings. Min-opposedbosses 4| on the upper and lower covers 15' and 8. Also push fitted uponthe same 40 hingepin v39 is the. hub A2 of a double quadrant gear 43.Afterassembling the parts shown in Fig. 4, we believe thatit is best toweld each pair of the hubs 38A together or to detachably connect. them.by such meansas'a' right and left hand nut (not shown), and to weld thesection 43A of the quadrant gearto the adjacent radius link 38 or :todetachably oonnect'them by such Movement is imparted to'thelabovedescribed 7 mechanism thru thejlobes 4.4 on the ,camufl 5 5 which isindicated as rotating clockwise. When the lobe 44 engages the outer raceof the roller bearing 3|, which we will henceforth refer to as a roller,the roller is raised and with it the piston 24 to compress the charge ofair ahead of it. The path of the roller is guided and fixed by theradius links 38 which, being secured to the sections 43A of the doublequadrant gear 43, raises this section with them. Since both of thesections 43A and 43B are integral and angularly disposed, the section43B moves down as the section 43A moves up, and since section 53A of onequadrant gear meshes with the section 43B of the adjacent quadrant gear,and vice versa, adjacent pistons on each side will reach their lowestpoint as the intermediate piston reaches the highest point as clearlyshown in Fig. 4. A perusal of Fig. l, shows that by having the radiuslinks hinged to the left of a roller, when the direction of rotation ofthe cam is clockwise, each roller 3| will be raised in the direction ofrotation and not against it.

The above bell crank piston-return mechanism is, we believe, animprovement over the one shown in Fig. 6, in which a bell crank of theconventional type is shown. Although this mechanism is more simple andrequires but one bell crank to two cylinders, it causes one roll 3| tobe lifted with and the other against the direction of cam rotation. Inthis instance, the double quadrant gear, which constitutes a bell crank,is eliminated and a pair of radius links 383. are joined integrally withthe hub 38A and the radius links 38 to form a double arm bell crank. Inthe arrangement the same hinge pin 39, wrist pin 33, roll 3!, andconnecting rod 26, are used and mounted as previously described.

The inherent disadvantage in the above mechanism may be overcome in avery simple manner as shown in Fig. 7, by slotting the end of the radiuslinks 38B to form the jaws 46 adapted to straddle an extended wrist pin33 or a pin carried by said wrist pin as we have shown. The wrist pin 33is made hollow for the reception of a pintle pin 41 which has itsprojecting ends flattened to provide parallel bearing surfaces 48 forengagement of the jaws 48 over which said laws may slide, and theshoulders 49 for retaining the pintle pin 4! within the wrist pin 33.The pintle pin 4'! is made a snug turnable fit within the wrist pin sothat it may adjust itself to the radial movement of the radius links383. The combination of the jaws and pintle pin takes the place of theteeth 430 on the double quadrant gear 43 and a sliding action issubstituted for the rolling action of the gear teeth. In this instance,it is necessary to provide one bell crank for each cylinder since theslotted links 383 of one bell crank engage the pintle pin 41 of thepreceding bell crank and hence all of the rolls 3! are raised in thedirection of cam rotation.

The piston-return mechanisms so far described must be accuratelyconstructed in order for them to function in the most efiicient manner.Accurate work brings up the cost of manufacture and to keep this downtwo different means have been shown. In Fig. 4, the side 44A of the camlobe 44 has been relieved, and in Fig. 8, the slotted radius links 38Bhave been made in two sections hingedly connected together, with theirrelative movement limited and cushioned. The hub section 50 is formedwith two knuckles and the jaw section 5 2 with three knuckles 53. Thruthese knuckles the hinge pin 54 is passed, the

same being a snug fit in the knuckles but adapted to be removed byengaging its head 54A. Compression springs 55 to take the normal loadcoming on the section 52 are inserted between the two sections 55 and 52to cause the roller 3| to always remain in contact with the cam surface45A whereby the cam lobe 44 does not have to be relieved to compensatefor lack of exacting workmanship. A further advantage is the absence ofshock or noise when the rollers are engaged by the lobes. The upwardmovement of the jaw section 52 is limited by the upper contactingsurfaces 56, and the downward movement, which the springs 55 may effect,is limited by the lower contacting surfaces 51. It is evident that botharms of the bell crank of Fig. 6, may be made adjustable.

The cam 45 is secured to the Vertical drive shaft 58 supported on adouble row ball hearing 59 in the cartridge 65 mounted within thecompressor base. The base has a diaphragm 62, positioned at the junctionof the frusto-conical portion I with the cylindrical portion 3, providedwith the boss 63 within the frusto-conical portion 4 and a boss 54within the cylindrical portion 3, both bosses being axially aligned andbored for the reception of the barrel portion 60A of the cartridge 65whose position is fixed by the nut 65, threaded upon its exterior andagainst the bottom of the boss 64 thereby clamping the cartridge flange66 against the top of the boss 63. The inner race 59A of the ballbearing 59 is clamped against the hub 61 of the bevel gear 68, which inturn is clamped against a ring 69 formed on the shaft 58, by the nut 10.The outer race 59B is confined between the interior shoulder H on thecartridge 60 by the cover plate 12. A shoulder 13 is formed on the shaft58 adjacent the lower cover 8. The lower cover 8 is provided with anupper diaphragm 1.4 and a lower diaphragm 15 spaced apart to form anintervening exhaust manifold 16 between them and the outer cylindricalenclosing wall 11, which forms the boss H, and the inner cylindricalenclosing wall 13, spaced from the median line 79 to provide acylindrical chamber 80 for the reception of the lower roller bearing 8|,whose outer race SIA is retained between the annular shoulder 82 formedas part of the enclosing wall 78, and the cover plate 83 secured to thediaphragm 15 by the cap screws 84. The inner race 8IB is retainedbetween the shoulder 13 on the shaft 58 and the spacer 85 between thehub 86 on the cam 45.

The annular intake manifold 81 and the cylindrical bearing chamber 88are formed similarly. The upper cover i5 comprises the upper diaphragm89, the lower diaphragm 90, the outer cylindrical enclosing wall 91, andthe inner cylindrical enclosing wall 92 having an annular shoulder 93between which and the coverplate 94 is the outer race 35A of the rollerbearing 95. The inner race 95B rests upon a spacer 96, similar to thespacer 85, supported by the hub 86 of the cam 45. v

The bevel pinion 91 is the direct means of imparting movement to thebevel gear 68. This pinion is secured to the shaft 98 which is supportedon its inner end by the roller bearing 99 whose inner race 99A ispositioned against the shoulder me on the shaft, and whose outer race99B is positioned against a shoulder IOI formed on the far end of theannular bearing chamber H32 .supported by the bracket H33 which extendsfrom the walls of the lower cover 8. The

outer end of the. shaft 98 is supported bythe double row ball bearing:IM whose inner race {04A is clamped against the spacer contactsthe hubof the pinion 91; by the nut I06 threaded upon the shaft 93. The outerrace I043 is confined between an inner'annular shoul= der I61 on thebearing chamber I08 of the oartridge I09 mounted in the bearingextension III;

. on the base I by the cover plate I II securedto the bearing extensionby the. cap, screws" II2 which pass thru a flange II3 onthe cover plateand the fiange II4 on the cartridge. The cover plate I II is provided.with the conventional grease I5 and are removable with said cover.

formed in the piston 24 is by the piston-return mechanism,airwithinfthe' cam chamber secured to the upper diaphragm the valve chambercap thru the pipe IZI grooves II5 for. the retention of lubricantswithin the'bearing. The prime mover'for the compressor may be directconnected to the shaft 98 by a flexible coupling or indirectly connectedby a. multiple belt drive, for instance, no method'beingshown. v v I Airenters the intake manifold 81 thru one or more suitable air filters I I6(two being shown) $9 of the cover The air passes from the manifold 81thru the ports I I1, lower diaphragm 95 adjacent each cylinder 20, intothe cam chamber 5A. As a being brought to its lowest position veys airfrom the manifold to a receiver (not shown). j i

From the above description and with reference to the drawings, it isevident that our compressor may be readily assembled and disassembled indrive pinion unit may be removed as units. The such, vand the top coverexpose the cam and allthe piston-return-mecha? nisms.

a by unscrewing the The compressor may be separated at the lower cover Bwith'the basev I,' and nuts 65 the whole gear asjunction of the semblymay be removed from the basei chamber 9A, but in our device this heatedair There is always, considerable heat generated during the compressionofair and some of this heat is transferred thruthe structural parts. andgiven off to the air' as radiated heat.

this heat is given off. to the. air within the cam and-the radiatingmedium is-cooled by the-cooler exteriorair sucked into the cam chamber9Aand then passed on thru the ceiver.

providing radiating fins-I24 on the cylinders 24. It may also be pointedout that heat from the cylinders and the pipes'I2I may be furtherdissipatedby extending the shaft 58 thru and beyondthe coverplate-94-toreceive a fan I adapted to take its air thru-the cylindricaltunnel I26 formed by asheet metal shell I21 attached to the valvechamber cap I2EI- and extending from the junction line of the base andlowercover 8 to'ab'ovethe .fan' blades- I25A-,-wherebyaccidental contactwith thefan blades is prevented. *Th'e called, are shown'dotted mingle;only. I05, which and piston return 'mech the oil dropping on the gear 11and the interior of the A pipe I23 threaded into the wall 11communicates with the chamber I22 and con}.

I5 may be lifted off tov plug I 5Il-for draining;

Much of 1 cylinders was the re-" a To further facilitatejthedissipation'pf heat we also employ the well known means of,

valves and into'fthe receiver.

The head ZQAbfeLCh-piston 24 for the reception [of a valve plate I52,secured 'to theahead 24A b I53, in whose bottom face is milledspaced-apart fan and guard, "which thetuhnel shell In order tolubricate' ou'r compressor when itis standing on'the side' ofa' hill {aswell as when it isworking'on a level street,vve bring the oil to the topof .th'esha'ft '58 an'd let it work down thru the upper roller bearing95'onto aslightlydished disk I28; rhountedon the it is thrownby=centrifuga-l force anisms ontothe pistons from which the surplus oilfinds its Waydo cam hub 86,from'which i vvnwardthru the lower rollerbearing 8 I ontotheftop-of the bevel gear 68 from which some of; itworks into the .roller bearing 99,1i0nto the bevel pinion 91, andalongthe shaft 98 into the ball bearing I04. Some of a small aperture I29.int e gear web and thence thru, the lowerball bearin'gi 59 into'th'esumpI30 formed below and asa part of thecartridge chamber 60B; The majorportion of the oil finds its'way' to the sump I30 thru thef'aperturesI3I 68 finds its way thru which bleedthe oil dammed up on --thediaphragm 62 bytheflboss'63. "Submerged in theflsuinp I30 is a rotary'pumpof the conventional type having multiple spring-pressed impellers(nots'hown in detail) *slidably-mounted in the end of the-shaft 58 tomaintain a contact impeller chamber- I32 eccentric to the end of theshaft 58 which extends into said chamber. The Q6 pump casing I33comprises a top portion 134 and a cover plate I35 ,to'which a capI36 issecured, countersunk head screws "being .used' but not shown tofastenthe several parts together;

portion-I34 to human annular collecting chamber I31 havingcommunicatingapertures I38 whereby oil may find its way into saidchamber. Anintake aperture I39 leads fromthe collecting chamber to theinterior v of the impeller chamber. Oil entering the=impeller chamber*iscarried around by-the impeller blades I40 and forced out into thepassage in the "shaft 58 to begin another cycle. Thepump: casing-isclamped against a shoulder I in the cartridge 'chamber thru thedischarge apertu're'MI I42-inthe cap*I36 and up the bore l43- BIlB'bythe cover plate I46 threaded-upon the exterior of the cartridgefill'. Inclamping the casing against the shoulder, fa

I lead washer tMl-is pressed slightly against the shoulder I48 on theshaft 58 to form'a'se'al; The communicating apertures" I38 are extendedinto with the interior ofthe groove is cut in theperiphery'of thetopca'sing comrn'unication with the] settling chamber'; I49

formed by the cover plate I46 provided with a within "the compress'othruthe plug HI in the cover plate 94 or the shaft 58. r i" I While-allworking'partsof a compressor should be well"lubricated',; oil in areceiver is not desirableg :Ilil

' are balanced to 'wear and lubrication, =yet an undesirable amountofoilcanno't pass thruthe the countersunk head screws verticallyarcuated grooves; I 54 in alignment I over a series ofelongated'apertures I55 communicat- Freshoil' maybe placed g the compressorillustrated all parts 66 is counterbored ing with-the grooves I54- andthe interior of the hollow piston '24.- The-grooves I54 are some Whatw'ider-than the diameter of the apertures I55 beneaththem'whereby'a thinstrip of-spring Steel'FcOnstitutingthenvalves II8 may overlap milled.entirely thruthe valve plate I52 to form' the slots I56 which mergewithadjacent'grooves I54. The top of the piston chamber head 29A iscounterbored for the reception of the valve plate I51, secured to thehead 29A by the countersunk head screws I58, in whose bottom face ismilled spaced apart vertically. arcuated grooves I59 in alignment over aseries of elongated apertures I60 communicating with the grooves I59 andthe piston chamber 20A. These grooves I59 are also wider than theapertures I50 beneath them and for the reasons previously stated. Thesegrooves I59 also merge with the slots I6I. The slots I56 and I59 aremade Wider over part of their length to expose part of the valves I I8and II 9. The valves H8 and H9 are free to conform to the curvature ofgrooves above them when acted upon by air pressure beneath them. Whenthe piston 24 is lowered the pressure of the air within the cam chamber9A raises the valves .I I8 and flows thru the apertures I55 and theslots I55 into the piston chamber 20A. Whenthe'piston is raised pressurewithin said chamber lowers the valves I I8 and raises the valves H9 andair within the chamber is forced out thru the apertures I60 and theslots I6I on its way to the'receiver. When the piston 24 starts tolower, receiver pressure acts upon the top of the valves H9 and lowersthem. With this arrangement, the intake valves I I8 remain open duringthe downward movement of the piston which makes for efliciency in anycompressor.

' It is readily apparent that our compressor may be changed considerablyin appearance and arrangement withoutv departing from the basic ideasembraced in our claims in which we seek to set up our ownership of allthat comes fairly within their scope. I

What we claim as new is:

1'. A fluid displacement mechanism having in combination a plurality offixed radially disposed fluid displacement units each unit including acylinder, a piston slidable within it, a connecting rod having one endhingedly connected to the piston, and a cam roller associated with thefree end; a centrally positioned rotatable cam to cause a piston to bemoved inwardly in a cylinder to compress air within said cylinder; and abell crank piston-return mechanism having one arm including a quadrantgear and a radius link hingedly connected to the free end of theconnecting rod, and a second arm angularly disposed to the first arm andterminating in a quadrant gear adapted to mesh with the first mentionedgear of the preceding unit whereupon inward movement of the piston ofone unit causes outward movement of the piston of the following unit.

2. A fluid displacement mechanism having in combination a plurality offixed radially disposed fluid displacement units each unit including acylinder, a piston slidable within it, a connecting rod having oneendhingedly connected to the piston, and a cam roller associated with thefree end; a centrally positioned rotatable cam to cause a piston to bemoved inwardly in a cylinder to compress air within said cylinder; abell crank piston-return mechanism having one arm hingedly connected tothe free end of the connecting rod and a second arm angularly disposedto the first arm and terminating in a jaw having slidable connectionwith the free end of the connecting rod of the preceding unit whereuponinward movement of the piston of one unit causes outward movement of thepiston of the following unit.

I passing thru the valves to the 3. A fluid displacement mechanismhaving in combination a plurality of fixed radially disposed fluiddisplacement units each unit including a cylinder, a piston slidableWithin it, a connecting rod having one end hingedly connected to thepiston, and a cam roller associated with the free end; a centrallypositioned rotatable cam to cause a piston to be moved inwardly in acylinder to compress air within said cylinder;. a bell crankpiston-return mechanism having one arm hingedly connected to the freeend of the connecting rod and a second arm, angularly disposed to thefirst arm, provided with an end section having limited hinged connectionthereto and terminating in a jaw having slidable and hinged connectionwith the free end of the connecting rod of the preceding unit whereuponinward movement of the piston of one unit causes outward movement of thepiston of the following unit, and compression springs interposed betweenthe arm and its end section to take the normal load coming on said endsection.

4. A fluid displacement mechanism having in combination a plurality offixed radially disposed fluid displacement units each unit including acylinder, a piston slidable within it, a connecting rod having one endhingedly connected to the piston, and a cam roller associated with thefree end; a centrally positioned rotatable cam to cause a piston to bemoved inwardly in a cylinder to compress air within said cylinder; abell crank piston-return mechanism comprising a bell crank having itsarms formed in two sections having limited hinged connectiontherebetween and hingedly connected to the free end of the connectingrods of adjacent units whereupon inward movement of the piston of oneunit causes outward movement of the piston in the other unit, andcompression springs interposed between the arm sections to take thenormal load coming on the connecting rod section.

5. A compressor having in combination a casing; a cam chamber within thecasing; a detachable casing end cover mounting a bearing and formed toconstitute an intake manifold; an exhaust manifold; a piston-operatingcam in the chamber journalled in the bearing; a plurality of compressorunits disposed about and without the compressor units, thru the valves;and means 1 to convey air passing thru the valves tothe exhaustmanifold.

6. A compressor having in combination a casing; a cam chamber within thecasing; a casing end cover mounting a bearing and formed to constitutean intake manifold; an opposite end cover mounting a bearing and formedto constitute an exhaust manifold, either or both of said covers beingdetachably secured to the casing; a piston-operating cam in the chamberjournalled in the bearings; a plurality of compressor units disposedabout and without the casing each including a cylinder, a pistonslidable within it, and valves operable thru movement of said piston;openings in the intake manifold thru which outside air may enter the camchamber and pass with air within the chamber, which has been warmed byheat radiated from the compressor units, thru the valves; and means toconveyair exhaust manifold. (5

mounting a bearing and formed to constitute an exhaust manifold, eitheror both of said covers being detachably secured to the casing; apistonoperating cam in posed about and without the casing each includinga cylinder providing a compression chamber,

the chamber journalled inthe bearings; a plurality of compressor unitsdisa piston slidable within it, and inlets to the compression chamberopenable thru movement of said piston; openingsinthe intake manifoldthru which outside air may enter the cam chamber and pass with airwithin the chamber, which has been warmed by heat radiated from thecompressor units, thru the inlets; and means to con-' vey air passingthru the inlets to the exhaust manifold.

JAMES V, SHERIDAN. JESSE W. FORRESTER.

